[Problem] To obtain the positions of a plurality of detection devices relative to one another. [Solution] A detection device is provided with: a detection unit that detects an object from a first viewpoint; an information calculation unit that calculates first model information including shape information for the object in the first viewpoint using the detection result of the detection unit; a light source calculation unit that calculates light source information regarding a light source using a first captured image of a space containing the object and a light source for illuminating the object with illuminating light; and a position calculation unit that calculates the positional relationship of the first viewpoint and the object using the light source information as information used to integrate first model information and second model information, said second model information including form information obtained by detecting the object from a second viewpoint which is different from the first viewpoint.